A Physical Unclonable Function (PUF) is a function that is embodied in a physical structure and is easy to evaluate but extremely difficult to predict. An individual PUF component must be easy to make but practically impossible to duplicate, even given the exact manufacturing process that produced it. When a physical stimulus is applied to the structure, it reacts in an unpredictable way due to the complex interaction of the stimulus with the physical microstructure of the component. This exact microstructure depends on physical factors introduced during manufacture which are unpredictable. The applied stimulus is called the challenge, and the reaction of the PUF is called the response. A specific challenge and its corresponding response together form a challenge-response pair which is specific to a given component. Such a challenge-response pair is assumed to be steady. The identity of the component is established by the properties of the microstructure itself.
It is known to authenticate one component of a device by using the result of a PUF execution. For instance, the plastic body of a smart card may be authenticated via a PUF as explained in EP0583709-A1 publication. Such an authentication is limited to the identifying of a single component belonging to a device.
A known attack may be performed by replacing the genuine chip of a device by a fake one. As a result, a genuine body may be associated to a fake chip.
There is a need for increasing the authentication of the genuineness of an electronic device.